Bone tissue is used in a wide variety of clinical applications to repair and/or replace defective or damaged bones. The bone used in these applications include whole or entire bones, sections of bones, and/or ground bone including bone chips. Such clinical applications include spinal fusions procedures, craniotomies, and repair of compound fractures of long bones. Demineralized cortico-cancellous bone chips and finely ground demineralized bone powders are used as fill materials where there is a bone defect, for example, in the repair of “holes” resulting from surgical procedures where removal of parts of a bone or bones or teeth.
Bone harvested from a cadaver is stored frozen until release criteria, for example microbiological/virological testing, are satisfied. At such time, the bone is thawed, debrided of excess soft tissues on the surface of the bone, bone marrow is removed from the cancellous bone space, and the bone is then cut into clinically usable grafts. As a preliminary step in the preparation of small bone grafts, soft tissues must be removed from the exterior surface of the bone in order to permit assessment of the “quality” of the bone. Bone from individual donors may not be suitable for the production of specific types of bone grafts, specifically load-bearing grafts such as the iliac crest wedge, and by visually inspecting the debrided bone it is possible to assess whether or not the bone will be suitable in the preparation of small bone grafts. Thus, removal of external soft issues such as the periosteum is important in the processing of bone into small bone grafts.
Prior art methods for removing soft tissue from bone include mechanically removing soft tissue and by enzymatic digestion. These methods are disadvantageous in that they are labor intensive, expensive, and also in the case of enzymatic digestion, may introduce the potential of contamination of the processed bone with immunogenic foreign proteins (the proteolytic enzymes) and/or associated potentially infectious agents associated with the extraction of the enzymes from animal species which might harbor infectious agents.
The invention overcomes the problems presented by the prior art methods by providing a simple and convenient method of debridement. The method also provides the additional advantage of inactivating infectious agents which may be associated with the bone tissue being processed, such infectious agents including bacteria, fungi, virus particles, and prions.